The human form of coenzyme Q is coenzyme Q.sub.10 (see formula below), and it is presumed to occur in every cell of every organ and every tissue of the human body which have mitochondria. Coenzyme Q.sub.10 has the biological characteristics of a vitamin, and exists in human tissue in trace amounts as do the well-known vitamins. Coenzyme Q.sub.10 occurs similarly in the tissue of cattle, and hundreds or thousands of hearts from cattle may be obtained from slaughter houses and used for the isolation of coenzyme Q.sub.10 in pure form by a tedious and expensive process.
Coenzymes Q.sub.6 through and including coenzyme Q.sub.10 have been isolated from fermentations utilizing a variety of microorganisms. Again, these forms of coenzyme Q exist in trace amounts in fermentation materials and the isolation of the pure forms of coenzyme Q.sub.6 - Q.sub.10 from fermentation materials is a lengthy and costly process. ##SPC1##
These naturally occurring forms of coenzyme Q exist in other living species including many of the higher plants. Again, the occurrence is in trace amounts and the isolation of a pure naturally occurring coenzyme Q from such other living source materials is a large-scale process.
The production of pure forms of the naturally occurring coenzymes Q.sub.6 through Q.sub.10 in kilogram or hundreds of kilogram quantities involves anenormous processing of slaughter house tissues, fermentation materials, higher plant an enormous fish wastes or other materials of living origin.
Certain synthetic modifications of coenzyme Q.sub.10 have been found useful in the treatment of a human disease, i.e., periodontal disease. T. Matsummura, S. Saji, R. Nakamura and K. Folkers (international J. Vit. Nutr. Research 43, No. 4, 537-548 (1973).) produced evidence for the enhanced treatment of periodontal disease in humans by therapy with hexahydrocoenzyme Q.sub.4. The synthesis of hexahydrocoenzyme Q.sub.4 requires phytol which, in turn, is derived from the chlorophyll of plant tissue. Again, the dependence upon plant tissue is a disadvantage for hexahydrocoenzyme Q.sub.4.
Both coenzyme Q.sub.10 and hexahydrocoenzyme Q.sub.4 showed hematological activity in nutritionally deficient children who were anemic. Such hematological activity of coenzyme Q.sub.10 is potentially important in medicine as reported by A. S. Majaj and K. Folkers (International J. Vit. Research 38, No. 2, 182-195 (1968)).
The availability of the easy-to-synthesize, and on a very large scale, and relatively inexpensive 6-alkyl derivatives of 2,3-dimethoxy-5 -methyl-1,4-benzoquinone which are coenzymatically active analogs of the naturally occurring forms of coenzyme Q will greatly facilitate new therapy in medicine.
The choice of the specific 6-substituted analog of the human coenzyme Q.sub.10 to be used in medicine will depend not only upon reasonable costs and large-scale availability, but also on the route of therapeutic administration, duration of action and treatment, nature of the disease, and other variables. Consequently, not all of the various 6-alkyl, saturated and unsaturated, analogs will be equivalent or of equal potentiality for practical usage in medicine (veterinary or human). Some of these synthetic analogs will have advantages of usage over other analogs.